ICYMI, Async GRPO in TRL now supports LoRA and we wrote a looong blog testing it
> the adapter is a few megabytes, so the weight sync is a file instead of an NCCL transfer > 3 HF Jobs: 1 trainer and 2 vLLM replicas > the adapter travels through an HF Storage Bucket mounted in all 3 at the same path > a proxy in front of the replicas routes each rollout to the one already holding its KV prefix